This speech will change your life.

Since the advent of America's greatest learning institution, Youtube, commencement speeches have become the country's most reliable way to communicate clear messages to the youth of America about how to make the world better.

Stay Hungry. Stay Foolish. Or, What I regret most in my life are failures of kindness. Or, The really important kind of freedom involves attention and awareness and discipline, and being able truly to care about other people and to sacrifice for them over and over in myriad petty, unsexy ways every day.

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And these are nice sentiments and all, but they all disregard the most pivotal unguent for the advancement of humankind. And that mantra is this:

Have you ever dropped your keys down a sewer grate. What is that? That's some bullshit, right there.

These are not, in fact, the words of famed astrophysicist Carl Sagan, although they are widely attributed to him. These are actually, give or take an expletive, the feelings of Norm MacDonald, who delivered the address about not losing your keys to the audience of a fake university this week.

And there is no greater reminder of the brevity of a human life, nor of how small keys can be, nor of how wide grates can be than MacDonald's touching speech. The universe is a vast expanse created to suit many people, some wholly unlike you, and also grates, lots of them, sometimes directly underneath you, arguably too many of them, but who knows?

We can never know.

The only thing we can know about life is that we don't know why somebody put so many grates there, or for what reason, or when, or how. None of that information is available, except in our hearts.

"Remember this, if you remember anything," says MacDonald. "Do not fiddle with your keys over a grating."

We must learn to accept this. And we must learn to keep our keys in our pockets, even if it is super fun to play with them.

We can only hope to learn much later, as the darkness falls upon all of us, that that one smell was coming from the grate all along, and not from that thing that you were pretty sure was a candy bar when you stepped on it earlier.

And we can only hope that our keys will stay with us either way, all the way until our deaths, or until we find a real cool hiding spot for the duplicates.